Re: LTP hugemmap05 test case failure on arm64 with linux-next (next-20190613)

[Qian Cai]

> On Jun 16, 2019, at 9:32 PM, Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote:
> 
> Hello Qian,
> 
> On 06/14/2019 05:45 PM, Qian Cai wrote:
>> On Fri, 2019-06-14 at 11:20 +0100, Will Deacon wrote:
>>> Hi Qian,
>>> 
>>> On Thu, Jun 13, 2019 at 05:34:01PM -0400, Qian Cai wrote:
>>>> LTP hugemmap05 test case [1] could not exit itself properly and then degrade
>>>> the
>>>> system performance on arm64 with linux-next (next-20190613). The bisection
>>>> so
>>>> far indicates,
>>>> 
>>>> BAD:  30bafbc357f1 Merge remote-tracking branch 'arm64/for-next/core'
>>>> GOOD: 0c3d124a3043 Merge remote-tracking branch 'arm64-fixes/for-next/fixes'
>>> 
>>> Did you finish the bisection in the end? Also, what config are you using
>>> (you usually have something fairly esoteric ;)?
>> 
>> No, it is still running.
>> 
>> https://raw.githubusercontent.com/cailca/linux-mm/master/arm64.config
>> 
> 
> Were you able to bisect the problem till a particular commit ?

Not yet, it turned out the test case needs to run a few times (usually within 5) to reproduce, so the previous bisection was totally wrong where it assume the bad commit will fail every time. Once reproduced, the test case becomes unkillable stuck in the D state.

I am still in the middle of running a new round of bisection. The current progress is,

35c99ffa20ed GOOD (survived 20 times)
def0fdae813d BAD